Vatican II was one of the most significant events in the life of the modern Church. Between October 1962 and December 1965 the largest ever gathering of Catholic bishops answered the call of Pope John XXIII to let some fresh air into the Church. Completing the work of an earlier Vatican Council that had been cut short, and in a tradition of ecumenical councils dating back to the time of the Apostles, Vatican II laid the foundations for a renewal process that still continues. For this reason CTS have decided to republish the four major documents of the Council (known as Constitutions and named after their opening words in Latin), with brilliant new Introductions by some of today's leading churchmen, to encourage continued study of the Council in parishes and elsewhere. Sacrosanctum Concilium has been the cause of more controversy than perhaps any other document of the Council, since it initiated a liturgical reform more radical than any in recent Church history. Critics of the reform allege that many innovations since introduced in the Council's name were neither sanctioned nor intended by the authors of the Constitution. Here is an opportunity to discover the truth for yourself.